1. Field of the Invention
The present invention relates to a method for controlling the temperature of an electric motor, and more particularly to a method for controlling a temperature of an electric motor used in a multifunctional office apparatus.
2. Description of the Prior Art
Generally, various types of electric motors are essential components of electronic appliances, office automation apparatus, and other apparatus for varius applications. In particular, a multifunctional apparatus having a line scanner, a line printer, and related components which are integrated with one another contains a plurality of electric motors and generally such an apparatus has the characteristic of holding the temperature at the inner portion of the apparatus in a predetermined range of temperature. In recent times, electronic appliances and office automation apparatus incorporate high performance semiconductor elements and electric/electronic elements to improve the accuracy of the apparatus. Since the semiconductor elements and the electric/electronic elements are sensitive to temperature, the temperature may have an effect on the accuracy of the electronic and the office automation apparatus. That is, if the temperature increases over a specific temperature in the electronic apparatus and the office automation apparatus, the elements may malfunction or may be destroyed due to the high temperature.
As an electric motor rotates at a high velocity, a high temperature is generated by the electric motor which has an effect on the electric motor and peripheral elements. Accordingly, the accuracy of the electric motor and the peripheral elements may be degraded. In order to hold the temperature of the electric motor and the peripheral elements in a predetermined range in the electronic appliance or the office automation apparatus, it has been proposed that a heat sink be mounted in the electronic appliance or the office automation apparatus to radiate the heat generated. Another proposal is that a temperature sensor be mounted inside the appliance to control the temperature in the electronic appliance or the office automation apparatus by controlling electric current supplied to the electric motor.
According to the conventional art as described above, however, such a heat sink or temperature sensor mounted in the electronic appliance or the office automation apparatus would substantially increase the manufacturing cost of the electronic appliance or the office automation apparatus. Furthermore, the method of controlling the electric current supplied to the electric motor to prevent the temperature of the electric motor from increasing may result in the motor not generating a torque, resulting in degradation of the reliance of the products.
Based on my observation of the art, then, I have found that what is needed is a method for controlling the temperature of a motor in an applicance which does not require a heat sink or a temperature sensor on the motor. Moreover, this method for controlling the temperature must not interfere with the operation of the motor such as to lead to loss of reliance of the appliance.